Effect of the heliospheric interface on the distribution of interstellar hydrogen atom inside the heliosphere

TL;DR

This paper models how the heliospheric interface influences the distribution of interstellar hydrogen atoms within the heliosphere, highlighting the importance of considering these effects for accurate data analysis.

Contribution

It introduces a new simplified model that incorporates key effects of the heliospheric interface for analyzing hydrogen atom distributions.

Findings

Distribution of H atoms is significantly affected by the heliospheric interface.

Effects are notable both at large distances and near the Sun (1-5 AU).

The new model can improve interpretation of Ly-alpha radiation data.

Abstract

This paper deals with the modeling of the interstellar hydrogen atoms (H atoms) distribution in the heliosphere. We study influence of the heliospheric interface, that is the region of the interaction between solar wind and local interstellar medium, on the distribution of the hydrogen atoms in vicinity of the Sun. The distribution of H atoms obtained in the frame of the self-consistent kinetic-gasdynamic model of the heliospheric interface is compared with a simplified model which assumes Maxwellian distribution of H atoms at the termination shock and is called often as 'hot' model. This comparison shows that the distribution of H atoms is significantly affected by the heliospheric interface not only at large heliocentric distances, but also in vicinity of the Sun at 1-5 AU. Hence, for analysis of experimental data connected with direct or undirect measurements of the interstellar atoms one necessarily needs to take into account effects of the heliospheric interface. In this paper we propose a new model that is relatively simple but takes into account all major effects of the heliospheric interface. This model can be applied for analysis of backscattered Ly-alpha radiation data obtained on board of different spacecraft.